Spoiler alert! Do not read further if you haven't watched the latest The X-Files episode,"Mulder & Scully Meet the Were-monster."

The X-Files embraced a new twist when it came to the were-monster Mulder (David Duchovny) and Scully (Gillian Anderson) were attempting to track down: he was not a human who transformed into a lizard-esque creature; rather, his natural form was lizard-esque, and he was unwillingly turned into a human named Guy Mann (Rhys Darby). The plight led to a sharp exploration of humanity, as Guy found himself compelled to get a job (that he despised), fantasize about sex (with Scully) and discover that the true joy of humanity is spending time with non-humans (like his new dog).

For Darby, landing on the right tone for Guy was key. “That was the difficult thing, to get the tone right,” he says. “Because of the character and the complexities of his existence…he was naïve and also frustrated. He didn’t want to be here. At the same time, he was also very comedic. And to be believable but also have the audience believe, perhaps, that he wasn’t telling the truth…all I had to draw upon was myself. I often feel out of place, so I guess it was kind of perfect for me, really. Why am I here, no one knows who I am and why am I in this situation? That kind of led to what Guy Mann became.”

Getting into Guy’s natural form for some key scenes—a stand-in was used when Guy was in full-on lizard-mode—also proved helpful for Darby to get in the right head space to play the character. “I had the full arms and head and things like that for some transformation and some close-up pieces,” he says. “So I still had to go through five hours of makeup to get that part done…it just added to the creepiness. It made me believe in who I really was, because I got to be that. That helped. It was quite creepy to watch your human side slowly diminish over time as you're looking in a mirror. Becoming this lizard man, it was certainly off-putting, and I don't think I'll ever forget it.”

Darby acknowledges he got to do a lot during his time on The X-Files. “The crux of the episode is the story I tell [Mulder],” Darby says. “I really lived it; I did everything. I got to hang out with Mulder. I got to be in a fight sequence. I got to get passionate with Scully. I got to be a creature. I got to run around naked in a forest.” He also added, “The thing that will stick with me—aside from the fact that I got to act alongside those two actors—will probably be when I said farewell to Mulder [at the end]." For Darby, that scene "was emotional. It was the last scene we shot, and it was the final bit of the show. [Mulder] got to say his famous line, 'I want to believe,' and we shook hands, and I got lost in the forest…it made me like what you see when I talk to him, look up to him and say, ‘Thanks for listening to my story. I'm glad I met you.’"

The hour was also an important one for writer/director Darin Morgan, who last penned a series episode in 1996. He spoke with TV Insider about coming back to the show, the Easter Eggs fans can spot in the hour (and the one that didn’t make it in) and more.

What was it like when you sat down and started to write for Mulder and Scully again after all these years?
[Laughs] To be honest, I didn't really think about it. I can't say it was like old times, and I can't say it was incredibly difficult. It was like, I guess, revisiting old friends. They've changed, but they're still basically the same. It wasn't that hard to write for them again, to be honest.

And how was it directing your first X-Files episode?
That was kind of hard, simply because of the show. I hadn't directed an X-Files episode before. I did a couple of episodes of [The X-Files creator] Chris [Carter’s] other series, Millennium. But the directors I worked with [on X-Files] were really experienced directors, like Kim Manners, Rob Bowman, David Nutter—really great directors.

Doing the show, it's just really difficult. Because you're shooting so many times on location, and late at night, and nothing prepares you for that. It's one thing to be shooting on a soundstage or something for long hours; it's another thing when you're out until four or five in the morning and you know you're shooting in a different location. It physically wears you out. I think a lot of our main directors [in the original series] were a little bit younger than we are, the guys directing it now. It was physically challenging, more than anything else. But we have a great crew. We've worked with most of the members of the crew, either on the show before or other shows that shot in Vancouver. That was really helpful, because they're friends and very supportive.

We've never seen a Mulder like this before—middle-aged, full of doubts about his life’s work on a deeper level. What did you tap into here that you never got to do on the original show?
When I was approached about doing the series again, as excited as I was, I was nervous for the same reasons Mulder had about going back and starting the X-Files again. [I thought,] "I've done this before, what's the point of doing these weird stories?" Also, [there was] the fear that people weren't going to watch it, regardless of what we did. So I was hesitant. And then I realized, I should put all of that stuff into Mulder. It makes sense; you have to acknowledge the passage of time for these characters. Mulder is an older man than when we were last doing it. And anyone, regardless of their profession, when they reach a certain age, they start wondering, "Is this the wisest way to spend my life?" So I took that stuff, gave it to Mulder, and hopefully people will be able to recognize it.

One of the fun things about the hour was when you brought back Tyler Labine and Nicole Parker-Smith as stoners…after they appeared twice in the original series in the same roles. What led to that particular callback?
[Laughs] If you need two stoners, why not try to get the original stoners? They were in two of our original episodes. We didn't know if they'd be available, but it worked out. I don't know how many people will pick up on that. I don't how many people were watching the show back then, but it was a [fun] callback to say those two have been finding different ways to get high for the past two decades. I thought it was a funny idea.

You’ve gone on the record to say that you don’t buy that Scully believes she’s immortal. [An idea first brought up in Morgan’s Emmy-winning “Clyde Bruckman’s Final Repose.”] When you were writing this hour, what internal debate did you have about playing with that fire again? And do you think Scully believes she’s immortal?
[Laughs] Now you're really making me play with fire. That was a playful way to acknowledge that that's part of their past history. Or, past history of the show. I, personally, hope Scully knows she's making a joke, and that she doesn't really think she's immortal. I'm sure others will interpret it differently. It's all you can do: you do a thing and people will take it in their own way and run with it. I have a lot of those references to the old series. Hopefully, older fans will pick up on some of them and get a kick out of it. Hopefully that one is one they pick up on.

A tribute to former X-Files director Kim Manners in the hour.

It really did feel like a love letter to the show—there was Mulder’s red Speedo; the tribute to Kim Manners and Jack Hardy in the graveyard; Mulder’s cell phone playing the show’s theme song; Scully bonding with a dog on a case. Even Mulder looking through the Fox mask felt like a lovely wink. Was there anything you wanted to get in that didn't make the cut?
In the scene where Mulder is talking to Scully and she's just on the bed listening to him go on with his crazy theories, she was supposed to be wearing an old New York Knicks t-shirt. But we didn't clear something legally. So that's my one disappointment, that we didn't get that one in. I think the 'shippers would have went nuts over that.

That’s incredible. Speaking of that speech, what was it like writing Mulder debating himself?
My fear of writing was going on—that Duchovny was going to get mad at me for making him learn all those words. That's the fear. He did, much to my amazement [learn it]. It was actually a couple of lines longer; we had to trim a couple of lines out. I'm sure when Duchovny sees the episode, he'll see he had to learn lines that didn't make it. That's a huge, huge scene, but he pulled it off. Hats off to him.

Is there anything else you want to say about revisiting these characters?
The only general thing is, now that some episodes have been seen…The X-Files was a unique show because the fans all had a different idea of what they liked about it; it was different. Sometimes someone liked the mythology. Some preferred the standalone monster of the week. Some people liked the comedy episodes, some people didn't. And so, knowing we're doing six, we knew that some people weren't going to like certain episodes.

I'm sure there's some frustration from people watching, because they're not used to that anymore: shows being really different from episode to episode. That's what the show always was…it felt like that was the way to do it. I'm not apologizing for that. I'm just telling fans, if you didn't like this particular episode or one of the other ones, wait until next week [which] will be entirely different. Maybe they'll like that. It's very difficult to appeal to everyone at all times. That's been the weird thing about going back. I knew some people were going to be unhappy about certain things, and there's nothing we can do about it.